Diagnose my xr plz?

[jado6006]

Hello fellow crawlers & those that know more than I! I was out putting my xr10 thru its paces earlier, & had an issue. 1st, equipment- twin micro winders,cc bec(6v), novak dig, hitec 7990 monster,bohemoth,utra, turbo servo, all controlled by a dx3c. So after 3 or so 1300mah packs, the servo starts glitching on me. And once it started, it didn't let up. I'd pick it up, & it'd steer fine, then it'd stay locked full right or left. Other times, it wouldn't react to my input at all. Just stayed straight. It kinda did every weird thing a servo can do. Then, i pulled the plug. All the elctrnx are new. Wanna know what you think before i tear into this thing.

[rangercat23]

Do you have your BEC wired in properly???

[OFFROADRCKOREA]

Yep sounds like a BEC problem and power issue however it could easily be a signal issue. I would start checking those wires and plugs in your rx. Easily trouble shoot by trying another RX if you have one laying around. Hook another servo into the RX to trouble shoot the rx if you can. Those are the easiest elimination steps before ripping it all apart. Also what is your BEC set too?

LIK

[Solitaire]

I'm betting on a missing ground from servo to Rx.

[jado6006]

My bec is set at 6 volts. Was thinking about bumping up to 7.4 to get the most outta my servo. Also, how would i lose the ground from the servo to the rx? ya mean a bad prong in the plug? Sorry, i'm kinda gettin a crash course in expensive moa-oligy. I had a single esc/dig equipped berg a few years back, & some shaftys, but no fancy shmancy (pain in the arss?) twin esc setups.

[jado6006]

Ok, so i checked the wiring. This is new stuff to me. The yellow servo wire is still in its plug going to the rx, but black & red are wired to the bec itself. I assume this would be a better(?) scheme to deal with this servo's demands? Would i be better suited to going back to a conventional setup, with the bec coming off the esc? If it sounds like i didn't wire this rig myself, its cuz i didn't. Just got it in one of those crazy trades that went from zero to done, in an hour.

[Trubble]

Originally Posted by jado6006

Also, how would i lose the ground from the servo to the rx?

Originally Posted by jado6006

The yellow servo wire is still in its plug going to the rx, but black & red are wired to the bec itself.

Add another black from the servo to the receiver.

[jado6006]

Guess i just "Y" it off? Does it matter where in line i wire it? Say, closer to the servo, or closer to the rx?

[OFFROADRCKOREA]

Y not bump that servo up to 7.4 volts? u may have simply had a weak battery and the servo pulling all that power could have easily caused the problems you described.

LIK

[jado6006]

I suspected that also. So, i plugged in 2 more packs that i knew were charged & healthy. Little 30c, 3s jobs. I'm intrtrigued about adding another ground tho. I'm just new to this whole setup, so not eager to start chopping into the wiring.

[envious8420]

My last spektrum did the same. turned out to be a bad pot in the radio. try tapping on the back of the radio around the steering wheel. when mine was acting up tapping on it would make it go back to center when it would lock the servo.

[rangercat23]

I use this set up (the BEC) in all my trucks.

Essentially the same thing for a MOA.


.

[jado6006]

Excellent dude! That's how mine seems to be situated also, except i don't have another ground from the servo to the rx. Going to add that next.

[mammoth]

Originally Posted by jado6006

Excellent dude! That's how mine seems to be situated also, except i don't have another ground from the servo to the rx. Going to add that next.

Spectrum needs the extra ground for some reason. Hook the ground to your rx and you should be good to go!!!

[crawler nut]

As said many times add the ground wire between the servo and rx. Had to do it to all my rigs that I still run with my spectrum. And bump the bec up to 7.4v. Then you should be good to go. If not then its probably a bad pot.

[rangercat23]

Originally Posted by mammoth

Spectrum needs the extra ground for some reason. Hook the ground to your rx and you should be good to go!!!

I run Futaba and had to use the ground as well because of some glitching initially.

[jado6006]

Well boys, seem to be spot on as usual. I added the ground between the servo & rx, & all seems to be fine now. The only little hiccup on my mind now is why did it take 3 packs for this to start happening? Did you guys have it happen immediatly, or after a few packs also? Cuz i've only run it for 10-15 mins since the added ground. Guess i'll find out. Thanks again fellas.

[jado6006]

Well crap! Got less than halfway thru the 1st pack, & the bug is back! I don't understand. I tested the servo on another rig, it's fine. The rx seems ok too. I pulled it out of a glitch/trouble free scaler cuz i needed the 3rd ch, & had a near new 2ch. to stick in, in its place. So, what's the deal with a bad pot? I'm embarrassed to say i'm not even sure what that is. I've never been a diehard spektrum guy. But have never had any trouble with'em either. Could one of you cats explain the pot thing to me(insert joke here)? Also, i didn't see anyone saying it was a fried bec either. Why? I've had a cc bec fry before, 2 actually, & neither seemed to do the same thing when it happened. Where do i go from here?

[envious8420]

try a different transmitter. the pot is behind the steering wheel. like i was saying earlier try tapping on the back of the transmitter, see if the steering starts moving around. mine wouldnt return to center, if i was making a turn and let the wheel go back to center the servo would stay locked in the direction i was turning.

[Charlie-III]

Originally Posted by envious8420

try a different transmitter. the pot is behind the steering wheel. like i was saying earlier try tapping on the back of the transmitter, see if the steering starts moving around. mine wouldnt return to center, if i was making a turn and let the wheel go back to center the servo would stay locked in the direction i was turning.

Pot = Potentiometer, or, variable resistor. As you move the center wiper it varies the resistence to one or both ends of the outer arc. Not much detail here, but it gives you an idea.

Potentiometer - Wikipedia, the free encyclopedia

They can get dirty or worn out, thus doing odd things instead of being smooth & linear.